1. A 700 N lady wearing stilettos walks with one foot on the ground. Find the pressure exerted on the ground by the lady assuming her entire weight is supported in one heel. The area of the heel is 2.00 cm2
Fluid Pressure
The term fluid pressure is coined as, the measurement of the force per unit area of a given surface of a closed container. It is a branch of physics that helps to study the properties of fluid under various conditions of force.
Gauge Pressure
Pressure is the physical force acting per unit area on a body; the applied force is perpendicular to the surface of the object per unit area. The air around us at sea level exerts a pressure (atmospheric pressure) of about 14.7 psi but this doesn’t seem to bother anyone as the bodily fluids are constantly pushing outwards with the same force but if one swims down into the ocean a few feet below the surface one can notice the difference, there is increased pressure on the eardrum, this is due to an increase in hydrostatic pressure.
1. A 700 N lady wearing stilettos walks with one foot on the ground. Find the pressure
exerted on the ground by the lady assuming her entire weight is supported in one
heel. The area of the heel is 2.00 cm2
.
2. A 253 mL pycnometer (a standard vessel used for measuring and comparing
densities of liquids or solids) has a mass of 170 g. Find its density in kg/m3
.
3. A plastic container has a mass of 55 g when empty and 175 g when filled with
alcohol. If the density if alcohol is 0.79 g/mL, what is its volume in L?
4. The density if a fuel is 700 kg
m3
. What is its specific gravity in g/cm3?
5. The plunger and the needle of a hypodermic syringe have areas of 0.5 cm2 and
0.0006 cm2
, respectively. To inject a vaccine, a nurse pushes the plunger with a
force of 5.5 N. Find the pressure (p1 and p2) is transmitted to the vaccine.
6. An object displaces 2.3 x 10-3 m3 of water when totally immersed into it. (a) What
is the buoyant force exerted by the water? (b) What is the density of the object if
its mass is 26 kg?
7. A nozzle with a radius of 0.250 cm is attached to a garden hose with a radius of
0.900 cm. The flow rate through hose and nozzle is 0.500 L/s. The speed of water
in a hose increased from 1.96 m/s to 25.5 m/s going from the hose to the nozzle.
Calculate the pressure in the hose, given that the absolute pressure in the nozzle
is 1.0 × 105 N/m2 (atmospheric, as it must be) and assuming level, frictionless flow
8. The standard water pressure supplied by water suppliers in the Philippines, such
as NAWASA, Maynilad, or Manila Water, is around 60 psi (pounds per square inch)
or around 4.14 x 10 5 Pa. Water enters the house through a pipe with an internal
diameter of 2.0 cm. From here, a 1.0 cm-diameter pipe leads the water to the
bathroom in the second floor that is 5.0 cm from the ground. If the flow speed at
the inlet pipe (the 2.0 cm diameter pipe) is 1.5 m/s, find the (a) flow speed, and (b)
pressure.
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